Refrigerating apparatus including heat exchange stabilizer means



Oct. 29, 1963 G. TINKEY 7 3, ,4 3

REFRIGERATING APPARATUS INCLUDING HEAT EXCHANGE STABILIZER MEANS FiledAug. 5, 1959 v 4 Sheets-Sheet 1 f6 INVENTOR.

OTTo G.T| NKEY ATTORNEY 0a. 29, 1963 o. G. TINKEY 0 REFRIGERATINGAPPARATUS INCLUDING HEAT EXCHANGE STABILIZER MEANS Filed Aug. 5, 1959 4Sheets-Sheet 2 FIG. 3.

INVENTOR. I Orro G. TINKEY J By ATTORNEY Oct. 29, 1963 o. G. TlNKEY. ,4

A REFRIGERATING APPARATUS INCLUDING HEAT EXCHANGE STABILIZER MEANS FiledAug. 5, 1959 4 Sheets-Sheet 3 FIG. 7. 22

I A o] INVENTOR. 4 c OTTO G.TINKEY Z ATTORNEY REFRIGERATING APPARATUSINCLUDING HEAT EXCHANGE STABILIZER MEANS Oct. 29, 1963 o. G. TlNKEY 4Sheets-Sheet 4 Filed Aug. 5, 1959 INVENTOR. OTTO G. TINKEY a 1. H m 5 mii. ww A w n" A ii. t u 3 H 0 :1 y, z w. A 1 f J: W m a L Fl 7 5 1 2 I)5 m 8 2 m 2 7 U a m 3 W, U N v, A r c ll ATTORNEY United States Patent3,108,453 REFRIGERATING APPARATUS INCLUDING HEAT EXCHANGE STABHJIZERMEANS Otto G. Tinkey, St. Louis, Mo., assignor of one-half to Mrs.Bonita E. Runde, St. Louis, Mo. Filed Aug. 5, 1959, Ser. No. 831,784Claims. (@Cl. 62-26%) The invention here presented is broadly in thefield of refrigeration apparatus and more specifically, a selfregulatingheat exchange system for hold-over solutions, mobile air conditioningand/ or refrigeration systems, two temperature refrigeration systems andthe like.

An object of this invention is to make simple or multiple cylinder orsingle and multiple-effect compressors practical and trouble free whilefully automatic in operation, by eliminating the almost inevitableliquid refrigerant and oil slugging of the compressor.

An object is to provide means to control one or more temperatures of amultiple temperature refrigeration system independently of each otherand regardless of the load on either the high or low side.

Another object is to pre-cool the liquid refrigerant going into thecoils.

Another object is to warm the cold refrigerant returning from thecooling coils into the compressor.

Still another object is to hold a reserve of liquid refrigerant which ismoving into the cooling coils, when using a restn'ctor expansion device,in order to slop over through the said cooling coils when the coolingload on the evaporator is reduced or to reduce the head pressure causedby extra high ambient temperatures.

Other objects and details of the invention will be apparent from thefollowing description, when read in connection with the accompanyingdrawings wherein:

FIG. 1 is a diagrammatic drawing of a two-temperature refrigerationsystem;

FIG. 2 is a schematic drawing of a two-temperature system as set forthby the applicant;

FIG. 3 is a section of FIG. 2, showing the addition of automaticexpansion valves;

FIG. 4 is a section of FIG. 2, but without the thermostatic expansionvalve;

FIG. 5 is a section of FIG. 2, but using capillary tubes instead ofautomatic expansion valves;

FIG. 6 is the same as FIG. 5, with the addition of automatic expansionvalves;

FIG. 7 shows two single coil stabilizers in series;

FIG. 8 shows three stabilizers connected in series;

FIG. 9 is a diagrammatic drawing of a multiple temperature refrigerationsystem showing the use of a multiported, multi-cylinder compressor.

There is a great consumer demand for two small refrigerators operatingsimultaneously, with one operating at just above freezing temperatureand the other operating at below freezing temperature. Presently, somemanufacturers use a separate complete condensing unit for eachtemperature refrigerator, thus entailing higher first cost, and higheroperating costs, in addition to extra electrical, friction, and othercondensing unit losses inherent to said extra equipment.

Other manufacturers use what is known in the art as secondaryrefrigerants, which usually requires building the freezer andrefrigerator together, with the freezer on top, which is the leastdesirable position in the minds of most users. Still other manufacturersuse various methods of holding back the above 32 degrees temperature,i.e., by means of suction pressure valves, weighted check valves, byadjustment of the refrigerant charge so it just slops over suificientlyto maintain an above 32 degrees temperature in the high temperaturerefrigerator and other methods, in an attempt to maintain a higher andlower temperature.

Practically all of these methods of using one compressor unit tomaintain two different temperatures in refrigerators, greatly reduce therefrigerating capacity of the [compressor WlhCIl it is working on thehigher temperature, by making said compressor operate at the reducedcapacity of the suction pressure which goes with the low temperature,all of the time it is refrigerating the high temperature. Because thecompressor must operate at times at high pressure, it cannot beproportioned for maximum efiiciency at low temperature operation andaccordingly, must operate at the lesser efliciency of the lowertemperature.

H. J. Macintire in his Handbook of Mechanical Refrigeration on page 56states that For general refrigeration, the multiple-elfect compressionhas not been popular because of the difliculty in adjusting the loads.

In an attempt to solve this problem, I connected a re fn'gerationsystem, as shown in FIG. 1, using a compressor 1, having a cylinder 2,which has a valve inlet port, shown at 3. =1 ported this cylinder,additionally, as shown at 4, thus making two inlet ports. Thiscompressor takes a full charge of suction refrigerant into the cylinderfrom a low temperature evaporator 5, through the valve port 3. Onuncovering the port 4, the higher back pressure suction gas from thehigh temperature evaporator 6, connected to the port 4, enters thelatter, thereby supercharging the compressor. The compressor, therefore,operates at all times on the high efliciency of the higher suction gaspressure, yet does not lose any efiiciency pumping the lower pressuregas from the lower temperature evaporator. However, I found such asystem impractical because sooner or later, a pocket of liquidrefrigerant and/ or oil formed in the evaporators during the idlecompressor periods. When the compressor started up on a running cycle,the refrigerantoil slug would be drawn into the gas compressor and wouldblow a head gasket, spring a crank-shaft etc. or at least, crack acompressor intake valve. This compressor damage happened so frequently,it made the use of the unit entirely undependable.

I, then, developed the embodiment, as shown in FIG. 2, which has madethe supercharged compressor entirely feasible and dependable,maintaining a temperature near 0 degrees F. in the freezer and anaverage of 35 degrees F. in the bottom portion to 45 degrees F in thetop portion of the above-freezing refrigerator.

In the embodiment, as shown in FIG. 2, the compressor 1 may have as manycylinders as desired, or if desired, two compressors may be used. Asingle cylinder 2 is shown for simplicity of description, having aninlet port 3. The compressor is fed refrigerant from thelowertemperature evaporator 5 through a compressor inlet valve 7, and,as a piston 8 reaches its bottom position, it uncovers a second port 4in the cylinder, through which the refrigerant from the highertemperature coils 6 is admitted, rthus supercharging the compressorcylinder and making it work at high efiiciency at all times. A suctionline from an evaporator 5 passes through its coil 9 in a stabilizer 11,and a suction line from an evaporator 6 also passes through its own coil10 in the stabilizer. This double coil stabilizer makes possible thecontrol of either or both temperatures of a two-temperaturerefrigeration system, independently of each other and regardless of theload on either the high or low side as hereinafter described. If thetemperature of either refrigerator goes too low before the unit shutsoff at a pre-determined setting of a desired temperature in onerefrigerator, the too-cold evaporator, or both evaporators, can be heldat any minimum temperature desired, by replacing a thermostaticadmission valve 12, as shown in FIG. 2, with an automatic pressureoperated expansion valve 13, shown in FIG. 4, which may be set tomaintain the minimum allowable pressures in their respectiveevaporators. Restrictor tubes 14, shown in FIG. 5, may also be replacedwith a bleeder type automatic pressure operated expansion valve. Whenthe evaporator refrigerant pressure drops to the pressure for which itsautomatic valve is set, the automatic valve opens to feed its respectivecoil sufiicient refrigerant to maintain the pressure for which the valveis set.

Better over-all refrigeration efficiency will result, if, instead ofreplacing thermostatic expansion valves and restrictor tubes withautomatic expansion valves, an automatic expansion valve 13 is connectedacross a thermostatic expansion valve 12, as in FIG. 3, or, across arestrictor tube 14, as shown in FIG. 6. This allows the automaticexpansion valve to supplement the thermostatic expansion valve orcapillary or restrictor tube.

As soon as an entire evaporator coil drops below the desired temperatureand corresponding refrigerant pressure for which its respectiveautomatic expansion valve is set, said valve opens and any excessunevaporated liquid refrigerant, not required to cool the evaporator,slops over into its respective stabilizer coil, in the stabilizer, asshown at 11. The stabilizer shell 23, surrounding said coil or coils, isconnected to a condenser 16 in such a manner as to act as a refrigerantreceiver and in addition have space for refrigerant gas above the liquidrefrigerant. The connection between the discharge end 22 of thecondenser and the inlet to the stabilizer shell, must be of sui'licientsize to pass all of the liquid from the condenser and also passuncondensed refrigerant gas from the condenser into the stabilizer.Therefore, any unevaporated refrigerant from the evaporator passing intosaid stabilizer coil 9 is immediately evaporated, thereby eliminatingliquid refrigerant slugging of the compressor. Also, by supplementingthe condenser with unevaporated refrigerant, at the point of contactbetween the uncondensed gas and the liquid refrigerant, the headpressureis lowered with an air-cooled condenser or its water-tower equivalent.Or, water is saved, Where cooling water is controlled by a pressureoperated Water valve, wasting water from a water pressure system.

The correct height of the refrigerant in the stabilizer is readilyindicated by the two trycocks and 21, or by gauge glass, sight glasses,float indicators or other such means. Trycocks are shown in thepreferred embodiment because the topmost trycock can be used as anon-condensable gas purge for the refrigeration system. A trycock orother valving means can be used with sight glasses for a non-condensablegas purge.

Since the stabilizer shell is the liquid refrigerant receiver, all ofthe heat extracted from the evaporators, plus most of the heat ofcompression is available, because of the fact that the stabilizer isconnected with the condenser 16, as shown in FIG. 2. Therefore, plentyof the heat is available around the stabilizer coils to evaporate allthe liquid refrigerant returning from the evaporators. Head pressure islowered because of the additionally cool condensing medium, therebyeffecting saving in operating costs. With sufiicient heat exchangesurface in the stabilizer evaporating coils, it is practicallyimpossible to slug liquid refrigerant through said stabilizer coils intothe compressor, and oil returning from the evaporator has any entrainedliquid refrigerant centrifuged out by the stabilizer coils orconductors, and the oil is broken into spray or mist by said centrifugalaction. Therefore, no compressor slugging occurs. This is not true inthe so called heat exchanger, wherein the liquid refrigerant is broughtinto thermo-contact with the returning suction gas from the evaporator.The amount of heat available to evaporate any unevaporated liquidreturning in the suction line is limited by the heat of the liquidcapacity of the condensed high pressure liquid refrigerant.

The necessity of lowering first costs and lessening maintenance hasforced manufacturers to abandon expansion valves and use restrictortubes wherever possible. When using a restrictor tube, it is necessaryto note that the size of the latter, both in cross-section and length iscritical in each particular refrigeration system. The amount ofrefrigerant charge is critical. Likewise, the restrictor tube and therefrigerant charge must be critically balanced for a pre-deterrninedmean pressure. Lower head pressure will cause a build-up of liquidrefrigerant in the condenser coils thereby starving the evaporator bynot completely filling the same. Higher head pressures cause uncondensedrefrigerant from the condenser to flow through the restrictor tube intothe evaporator lowering the evaporators capacity to pick up heat. Thisblowthrough of uncondensed refrigerant, sometimes causes liquidrefrigerant to slop over into the suction line, still further reducingthe evaporator capacity.

Greater self regulation will result, when using a restrictor tube as arefrigerant metering device, by the use of the stabilizer. Therefrigerant charge for a stabilizer system is adjusted to just till theevaporator at a pre-determined mean head pressure with a regulatedamount of liquid refrigerant remaining in the stabilizer receiver andthe normal carry-over of refrigerating effect into the stabilizer by thegas returning from the evaporator. Lower head pressure will cause abuild-up of liquid refrigerant in the stabilizer, thereby starving theevaporator by not completely filling the same, thereby reducing saidcarry-over of refrigerating effect into the stabilizer, thus reducingthe stabilizers supplementary cooling which raises the head pressure,which in turn assists in counter balancing the lowered head pressure.High head pressure causes liquid refrigerant from the stabilizerreceiver to blow through into the evaporator coil. The blow throughcauses unevaporated liquid to slop over into the stabilizer coil, thussupplementing the condenser, thereby lowering the head pressure. Due tothis action, lowering of the head pressure, a considerably greatercondenser temperature rise is necessary to blow uncondensed refrigerantinto the evaporator than is the case without the stabilizer; whereas, aconventional refrigeration system with a high pressure or a motoroverload cut-out must (can only) stop the compressor, thereby completelystopping all refrigeration. The stabilizer system will keep running at amuch higher condensing temperature. Although refrigeration effect willbe reduced in the latter, it will not be completely stopped as would bethe case in present day conventional refrigeration systems.

To minimize waste of refrigeration by the cold connection between theevaporator and its respective coil in the stabilizer, the latter shouldbe placed as close to the evaporator as it is physically possible toarrange. Where the evaporators are separated at some distance from eachother, the close connection between the evaporator and its stabilizercoils may be maintained with the same over-all effect by the use ofsingle coil stabilizers with the shells connected as shown in FIG. 7.Three or more coils may be connected with their respective single coilstabilizers, as shown in FIG. 8. When using two or more stabilizers, theconnections between them should tap the stabilizer shell nearest thecondenser at the top of the liquid level in the first stabilizercondenser, as shown at 17, and discharge into its next in linestabilizer shell as shown at 18.

In succeeding stabilizers, the connections between them should tap thestabilizer shell nearest the condenser at the top of the liquid level,shown at 19, and discharge into its next in line stabilizer shell, asshown at 20. When using two or more stabilizers connected in series andusing heavier than air refrigerant, the uppermost stabilizers should beequipped at their tops with purge valves, 24, or cocks for purging outair and non-condensable gasses. When using lighter than air refrigerant,the purge cocks should be located just above the liquid refrigerant inthe stabilizer shells.

By using multiple stabilizers, each placed as near as possible to itsrespective evaporator, as above described, insulated suction lines fromthe evaporators to the stabilizers, with attendant refrigeration lossesand possible objectionable frosting, sweating and dripping, areeliminated.

Since the compressed refrigerant from the compressor has had thesuperheat of compression removed by the condenser before it reaches thestabilizer, the latter coils do not superheat the refrigerantexcessively as it enters the compressor, yet does superheat it to complywith manufacturers rating requirements. In this connection, it is wellto note that many manufacturers of refrigeration compressors state intheir catalogue ratings that they will not guarantee theperformance'capacities of their compressors, unless the suction gas intosaid compressor is superheated to 65 degrees F.

When the suction line from the evaporator to the compressor is short, inbelow-freezing installations that have condensing units that are not ofthe hermetic type, having suction gas heated by the cooling of theirmotors, the suction coiled stabilizer, as shown in FIG. 2, is the mostpractical and almost the only way this suction gas superheating can beaccomplished. This elimination of compressor slugging and the slightsuperheating of the suction gas from the evaporator makes possible thepractical operation of the high efficiency supercharged compressor fordual or multiple temperature applications on an automatic unattendedbasis by porting the compressor cylinders at different points in theirstroke. In multiple cylinder compressors, one or more cylinders may havetheir main inlet valves ports isolated and different cylinders ported atdifferent points in the piston stroke to maintain the severaltemperatures in the respective evaporators. This may be illustrated by asituation such as automotive or marine air conditioning andrefrigeration where one has a multiple cylinder compressor, the mainpurpose of which is for air conditioning as shown at 6, FIG. 9, butwhere one in addition wishes low temperature refrigeration evaporatorsas shown at and 31 from the same compressor, this is attained byisolating individual cylinder inlet valves 33, 34, and 35 and cylinderports 28 corresponding to individual evaporators 6 whereby multipletemperatures may be obtained from the same compressor.

In using an evaporator consisting of a hold-over or eutectic solution2.7, in a container 26, as shown in FIG. 2 with refnigerant evaporatingcoils in contact with said solution, wherein the solution is frozen bysaid evaporating coils, as the solution nears complete freezing, therefrigeration load or amount of heat being given up by the solutiondecreases. Since the capillary tube or metering device tends to feed aconstant amount of refrigerant into the cooling coils, more and moreunevaporated liquid refrigerant will flood through said evaporating coilinto the compressor. By passing the refrigerant returning from thecooling coil to the compressor through a coil inside the stabilizermember any returning liquid is evaporated, to prevent compressorslugging and at the same time the head pressure is lowered, therebylessening the flow of refrigerant through the capillary tube, making thesystem self regulating to a certain extent, as well as reducing theamount of current required by the condensing unit motor.

The standby electric, friction and other losses of the compressor are,by and large, mostly taken care of on the colder cooling application. Bytaking advantage of the compressor supercharging application for thehigher temperature refrigeration, the latter is obtained almostloss-free, thereby resulting in a large saving of power.

There are disclosed a limited number of embodiments of the structure andit is desired therefore that only such limitations be imposed on theappended claims as are stated therein, or are required by the prior art.

I claim:

1. -In a two-temperature refrigeration system having refrigerantmetering devices thereon and having a charge of refrigeranttherethrough, a multiple-effect compressor having a cylinder therein, anupper inlet port and a lower inlet port in the latter, a condenserconnected to the compressor, multiple liquid refrigerant stabilizershell receiver means connected to the condenser, a low-temperatureevaporator connected through a coil in a stabilizer shell member to theupper port, a relatively high temperature evaporator connected through asecond coil in a second stabilizer shell member to the lower port, thebottom liquid receiver portion of said first stabilizer shell connectedthrough a refrigerant metering device to the low temperature evaporator,the bottom liquid receiver portion of the second stabilizer shellconnected to the high temperature evaporator through another liquidmetering device, said first stabilizer shell connected to the condenser, said second stabilizer shell member tapped to the first stabilizermember at the top of the liquid level in the latter thus all of the heatof vaporization passing through said compressor is made available forevaporating slugs from any one or more of the evaporators.

2. In a two-temperature refrigeration system having a charge ofrefrigerant therein, a multiple-effect compressor, a condenser connectedtherewith, a stabilizer shell means, a cylinder in said compressorhaving an inlet in the upper portion thereof, a second inlet port in itsbottom portion, a low temperature evaporator connected to the firstmentioned port by means of a suction line connected through a coil insaid stabilizer shell means, a higher temperature evaporator connectedto the second inlet port through a second suction line through a secondcoil in the stabilizer shell means, said shell means having inlet meansconnected to the discharge end of the condenser, said inlet connectingmeans between the condenser and the stabilizer shell means, includingthe shell means being of sufficient size to pass all of the liquid fromthe condenser together with any uncondensed refrigerant gas into saidstabilizer means, said shell having an outlet, and conduit meansconnecting the outlet with the low and high temperature evaporators.

3. The apparatus of claim 2 including adjustable automatic pressureoperated expansion valves positioned in the conduit means connecting thestabilizer shell outlet with the evaporator.

4. The apparatus of claim 2 wherein the stabilizer shell means is ofsufficient size to include a space for refrigerant gas above the liquidrefrigerant, the stabilizer means functioning to cool the liquid thereinand reduce the pressure therein below condenser pressure, and thestabilizer shell means including means to indicate the quantity ofrefrigerant in the shell, said last mentioned means being capable offunctioning as a purge means.

5. A multi-temperature refrigeration system having a refrigerant chargetherein and having refrigerant metering devices thereon, a multi-effectcompressor, a condenser connected therewith, stabilizer shell meanshaving liquid receiving portions, a plurality of cylinders in saidcompressor with pistons operating therein, each cylinder having anintake valve at the top of its piston 'stroke, the intake valve of onesuch cylinder isolated from its adjacent cylinders, said cylinder havinga second inlet port in its bot-- tom portion and an additional inletport in a portion intermediate the top and bottom ports, a lowtemperature evaporator connected to said isolated inlet valve by meansof a suction line connected through a coil in a first stabilizer shellmeans, a higher temperature evaporator connected to said intermediateinlet port by means of a suction line connected through a coil in asecond stabilizer shell means, a high temperature evaporator connectedto the bottom inlet port in said cylinder and to the top intake valvesin the additional cylinder in said compressor, by means of a suctionline connected through a coil in a third stabilizer shell means, thebottom liquid receiver portions of said shells connected by conduitmeans through individual metering devices to their respective low,higher and high temperature evaporators, the first shell tapped to thesecond shell at the liquid level of the latter, the discharge connectioninto said first shell being above its liquid level, the second shelltapped to the third shell at the liquid level of the latter, thedischarge connection into said second shell being above its liquidlevel, the third shell having inlet means connected to the discharge endof the condenser.

References Cited in the file of this patent UNITED STATES PATENTS2,071,935 Muflly Feb. 23, 1937 8 Smith Mar. 9, 1937 McLenegan Mar. 22,1938 Buchanan July 12, 1938 Candor Aug. 23, 1938 Gygax Aug. 29, 1939Kramer Jan. 14, 1941 Spofiord June 3, 1941 Buchanan Jan. 11, 1949McGrath Apr. 20, 1954 Sweynor Nov. 13, 1956

1. IN A TWO-TEMPERATURE REFRIGERATION SYSTEM HAVING REFRIGERANT METERINGDEVICES THEREON AND HAVING A CHARGE OF REFRIGERANT THERETHROUGH, AMULATIPLE-EFFECT COMPRESSOR HAVING A CYLINDER THEREIN, AN UPPER INLETPORT AND A LOWER INLER PORT IN THE LATTER, A CONDENSER CONNECTED TO THECOMPRESSOR, MULTIPLE LIQUID REFRIGERANT STABILIZER SHELL RECEIVER MEANSCONNECTED TO THE CONDENSER, A LOW-TEMPERATURE EVAPORATOR CONNECTEDTHROUGH A COIL IN A STABILIZER SHELL MEMBER TO THE UPPER PORT, ARELATIVELY HIGH TEMPERATURE EVAPORATOR CONNECTED THROUGH A SECOND COILIN A SECOND STABLIIZER SHELL MEMBER JTO THE LOWER PORT, THE BOTTOMLIQUID RECEIVER PORTION OF SAID FIRST STABILIZER SHELL CONNECTED THROUGHA REFGRIGERANT METERING DEVICE TO THE LOW TEMPERATURE EVAPORATOR, THEBOTTOM LIQUID RECEIVER PORTION OF THE SECOND STABILIZER SHELL CONNECTEDTO THE HIGH TEMPERATURE EVAPORATOR THROUGH ANOTHER LIQUID METERINGDEVICE, SAID FIRST STABILIZER SHELL CONNECTED TO THE CONDENSER, SAIDSECOND STABILIZER SHELL MEMBER TAPPED TO THE FIRST STABILIZER MEMBER ATTHE TOP OF THE LIQUID LEVEL IN THE LATTER THUS ALL OF THE HEAT OFVAPORIZATION PASSING THROUGH SAID COMPRESSOR IS MADE AVAILABLE FOREVAPORATING SLUGS FROM ANY ONE OR MORE OF THE EVAPORATORS.